Doctor Who: ''The Sontaran Stratagem'' UK Review

Donna and the Doctor roll out the welcome mat as UNIT, Martha Jones and the Sontaran menace return.

SPOILER WARNING: This is a UK review of episode four of Doctor Who's fourth season, currently airing on Saturdays on BBC One in the United Kingdom. If you've yet to see the episode, for whatever reason, read on at your own peril.

Buckling under the weight of past evidence, expectations for "The Sontaran Stratagem" were pitched somewhere around the Earth's core following news that this perennially troublesome two-parter was in the hands of one Helen Raynor, the writer responsible for last year's "Daleks in Manhattan"/"Evolution of the Daleks" – a double-bill pair so toe-curlingly amateurish and inept, the overall effect was like demanding every long-time Doctor Who fan leaned back while Russell T. Davies and crew urinated nonchalantly from above.

Miraculously then, "The Sontaran Stratagem" wasn't just not execrable, it came perilously close to greatness. Admittedly, a cursory glance at the episode synopsis might give you other ideas, featuring more hoary sci-fi clichés than the games industry's entire FPS line-up of 2007. We had the old mega-corporation-under-extra-terrestrial-control trope – already stamped into the ground by "Partners in Crime" at the beginning of this season – alongside shadowy institutions, warmongering alien marauders and even a boy genius with a penchant for teenage angst and humanity-hating melodramatics. Sure, we'll give the villains some kudos for orchestrating an invasion of the Earth's transport system by way of ATMOS – a carbon-emission neutraliser/SATNAV device with a tendency to drive its users off cliffs – even if it did seem slightly more work than necessary when you've got, you know, bloody big guns.

But here's the thing – it somehow all managed to work, largely thanks to Raynor's crackling script which graciously walked the tightrope between balls-out farce and affectionate sci-fi pastiche. It's deftness all the more startling considering the groundwork demanded by the episode, including the reinvention of classic Doctor Who villain the Sontarans, the return of the Doctor's old allies UNIT and, of course, Freema Agyeman's season three companion Martha Jones. Furthermore, Tennant and Tate clearly relished the episode's perpetual swings from square-jawed seriousness to faintly sadistic subversion. Witness, for instance, Donna and Martha's unexpectedly amicable opening encounter or the Doctor's gloriously eloquent acceptance of Donna's decision to leave the time traveller and return home – for a cup of tea, as it turns out. Even the deliberately anti-climactic car-based action set-piece relished the opportunity to mess with audience expectations.

General Staal of the 10th Sontaran Battlefleet, or ''Staal the Undefeated''

Leads aside, much of the episode's success can be attributed to Chris Ryan's pitch-perfect performance as the stumpy General Staal, managing to portray the Sontaran species as both a serious threat and jovially fogey-ish anachronism all at once. Predictably, Freema Agyeman still displayed the charisma and range of a dead fish – despite Martha's transformation from lovesick sap to Ripley-esque super soldier – but the episode's final fifteen minutes managed to play to her strengths, either asking her to lie very still or stomp around as an emotionless clone. Still, when Tate and Bernard Cribbins can steal the show with a genuinely moving yet utterly wordless reunion, you start to wonder whether bringing back Martha was the best idea in the world.

Ultimately though, "The Sontaran Stratagem" did pretty much everything a two-part opener should – swiftly shifting the pieces into place for next week's inevitably bombastic showdown. Let down by some uncharacteristically shoddy direction and art design, a willful reliance on stale sci-fi staples and one of the most idiotic cliff-hangers yet, the episode still managed to be smart and scary where it mattered but undemandingly entertaining throughout. Fingers crossed, the team hasn't dropped the ball for next week's conclusion, but if they have, hopefully it's on Freema's head and it's knocked some acting into her.